package src.leetcode.dp.hard_0115;

import java.util.Arrays;

public class numDistinct {
    public static void main(String[] args) {
        Solution solution = new Solution();
        System.out.println(solution.numDistinct("rabbbit", "rabbit"));
    }
}

class Solution {
    public int numDistinct(String s, String t) {
        int n = s.length(), m = t.length();
        int [][]dp = new int[n + 1][m + 1];
        for (int i = 0; i < s.length() + 1; i++) {
            dp[i][0] = 1;
        }
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                dp[i][j] = dp[i - 1][j];
                if(s.charAt(i - 1) == t.charAt(j - 1)) {
                    dp[i][j] += dp[i - 1][j - 1];
                    dp[i][j] %= 1000000007;
                }
            }
        }

        return dp[n][m];
    }
}
